Differentiate each of the following w.r.t. x:
(i) tan (log x)
(ii) log (sec x)
(iii) log (sin (x/2))
(i) Let y =tan(log x) z = log x
Formula : 
According to chain rule of differentiation
(ii) Let y = log (sec x) z = sec x
Formula : 
According to chain rule of differentiation
(iii) Let y = log (sin (x/2)) z = sin (x/2)
Formula : 
According to chain rule of differentiation
1